Crankcase ventilation system



Jan. 10, 1956 BROHN 2,730,086

CRANKCASE VENTILATION SYSTEM Filed NOV. 19, 1952 3 Sheets-Sheet l ATTORNEYS Jan. 10, 1956 H. A. BROHN 2,730,086

CRANKCASE VENTILATION SYSTEM Filed Nov. 19, 1952 3 Sheets-Sheet 2 W in? I 47 1 2/ {6/ if 4y I 46 v 12 j; A; A

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INVENTOR Zzrzzazzflfivi/r 0 z. W 5%TTORNEYS Jan. 10, 1956 H. A. BROHN CRANKCASE VENTILATION SYSTEM 3 Sheets-Sheet 3 Filed NOV. 19, 1952 INVE NTO R 5927/10 Q zaiz BY 24%,"

2,730,086 CRANKCASE VENTITATION SYSTEM Herman A. Brohn, Flint Mich, a'ssignorto General Motors Corporation, Detroit, Mich a corporation of Delaware Application November 19, 1952, Serial No. 321,453 10 Claims. (or; 123-41386 This invention relates to crankcase ventilating systems for engines and has particular relation to a crankcase ventilating system especially applicable for use in V-type engines for automotive and other uses.

crankcase ventilation systems as heretofore constructed may be classed as either breather systems or forced air systems; In a breather system it has been customary generally to provide merely a breather tube communicating with a crankcase or a camshaft gallery of the engine. Lubricating oil may be supplied to the engine through the tube and the tube may admit air or discharge air or both. Sometimes another inlet or outlet passage is provided either in the crankcase or the camshaft gallery of the engine, in an effort to obtain a circulation of air through the crankcase and camshaft gallery and from the motion of the vehicle with which the engine may be employed. When forced circulation systems are provided it has been proposed to put on extra fans or other circulating devices, adjustable vanes and battles and especially constructed passages. All of such expedients complicate the construction of the engine and increase both manufacturing and service costs.

It is proposed to construct an'engine in such a way that suflicient and adequate crankcase ventilation will be obtained by the use of structure; that is largely conventional but due to the design and arrangement of the various parts of such structure a flow of air through the crankcase and camshaft gallery for ventilation purposes will be inherent in theope'ration of the engine.

in the drawing:

Figure 1 is a longitudinal sectional view of an engine having a crankcase ventilating system embracing the principles of the invention.

Figure 2 is a transverse sectional view through'the engine disclosed by Figure l;

Figure 3 is a plan view of the lower side of the cover plate employed in closing the camshaft" gallery in the engine disclosed by Figures 1 and'2."

Figure 4 is a cross-sectional'view of the cover plate shown by Figure 3 and taken substantially in'the plane of line 4-4 on Figure 3.'

Figure 5 is a fragmentary longitudinal sectional view through the structure shown by'Figure'3'and illustrating a part of the outlet passagdleadirig frorn the crankcase ventilating system. Figure 5 is taken substantially in the plane of line 5-5-on Figure 3'looking'in the direction of the arrows thereon.

In Figures 1 and -2 the -engine" comprises generallynited States Paten 0 ice by which the pistons 26 are connected to the crank arms of the crankshaft 24.

. The cylinders 18 may be formed in the block 11 in banks or rows of aligned cylinders 28 and 29 with the axes of the cylinders in each row in obliquely disposed relation to an intermediate plane through the axis of rotation of the crankshaft of the engine. The space between the banks of cylinders 28 and 29 provides a camshaft gallery indicated at 31 and the space within the block 11 and below the inner ends of the cylinders 18 provides a crankcase indicated at 32. Any suitable means may be employed for cooling the cylinders and the heads of the engine, as for example the jacketed cavities 33 and 34 which may be formed in the block 11 and the heads 12 respectively. The inner walls of the jackets formed in the block 11 may terminate at the lower ends thereof in longitudinally disposed and spaced reinforcing columns 36 which extend between the front and rear walls 37 and 38 of the block 11 and which form an elongated passage 41 extending from front to rear of the engine and between the camshaft gallery 31 and the crankcase 32. Transversely disposed walls 42 and 43 are formed across the block 11 between the columns 36 and the walls of the crankcase below the columns 36 for structurally reinforcing the block 11 and for supporting the intermediate bearings of the camshaft and crankshaft which are disposed between the center bearings and the bearings at the opposite ends of the camshaft and crankshaft. It will be noted from Figure 2 that the upper edges of the walls 42 andc43 are: arcuate in formation and extend within the camshaft gallery Sll only far enough to provide support for the camshaft bearings. Between the intermediate walls 42 and 43 is a centrally and transversely disposed wall indicated at 44 and in which the central bearings for the camshaft and crankshaft are provided. It will be noted, however, that the wall 44 does not terminate in arcuate upper edges as do the walls 42 and 43 but extends across and upwardly within the camshaft gallery 31 to provide an opening 46 adapted to be closed by a plate or removable part of the wall 44 and indicated at 47. The wall 47' has flanges at the edges thereof adapted to engage the edges of the wall 44 forming the opening 46 andis' adapted to be secured in the opening 46 by bolts indicated at 48. The upper edge of the plate 47 terminates in closely spaced relation to a camshaft gallery cover 49 and the gasketed edges of which are secured to the block 11 by bolts indicated at 51. It will be apparent that the wall 44 including the plate 47 forms a centrally disposed wall extending entirely across the camshaft gallery 31 and the upper part of the crankcase 32 and which divides the interior of the engine into front and rear compartments indicated generally at 52 and 53 respectively. It will also be apparent that the front and rear compartments 52 and 53 respectively divide the camshaft gallery 31 and the upper part of'th'e crankcase 32 into different compartments which communicate with one another through the front and rear ends of the'elongated passage 41. V

The lower ends of the walls 42, 43 and 44 all terminate above the oil pan 54 which provides the lower wall for the crankcase 32 and in' such manner as to provide open communication between the front and rear compartments 52 and 53.

Air for ventilating the camshaft gallery 31 and the crankcase 32 is adapted to be supplied to the upper end of the front compartment 52 by an ordinary crankcase filler tube indicated at The filler tube S6 is'adapted to be connected to an opening formed in the front end of the coverplate 49 and to project upwardly therefrom in front of the inlet manifold 16 and carburetor l7". The upper end of the filler tube $6 is adapted to be 'closed by a conventional filter cap indicated at 57. The filter cap 57 is made in the form of an inverted receptacle and has a filter element in the upper end thereof. However, air can enter the tube 56 at all times through the annular space between the cap 57 and tube 56 and the filter element between the cap and the end of the tube. An engine fan 59 is directly in front of and somewhat below the filler tube 56 and filter cap 57. As the engine runs the fan will discharge a blast of air upon the upper front end of the engine and this blast of air will form a stream of air which will move upwardly between the blocks 28 and 29 and the heads 12 of the engine. As this stream of air approaches the inlet manifold 16 and carburetor 17 it will curve upwardly to fiow around and above the inlet manifold and carburetor and consequently will move toward the annular opening 58 between the filler tube 56 and the cap 57. The annular opening 58 therefore will be subjected to a forced draft of air from the fan 59 which will flow upwardly in the annular space 58 and through the filter in the upper end of the cap 57 and downwardly through the filler tube 56. The air that enters the front compartment 52 from the filler tube 56 will be confined to the space at the front end of the engine and in front of the wall 44. It will therefore be apparent that the front compartment 52 will be subject to a forced draft of air which will cause the air in the compartment 52 to move slowly downwardly on the opposite sides of the intermediate wall 42. The air moving downwardly in the compartment 52 eventually will flow across the bottom of the crankcase and longitudinally of the engine beneath the lower extremities of the walls 42 and 44 and will enter the rear end of the crankcase at the lower end of the rear compartment 53. In the rear compartment 53 the air will tend to flow upwardly on opposite sides of the wall 43 where it will flow from the engine through the discharge passage indicated generally at 61.

The discharge passage 61 is formed in such manner as to provide a separator element 62 and a draft tube 63. The separator element 62 is formed between a lower casing 64 and a divider element 66, the divider element being secured to the casing 64 at the flanged lower edges 67 thereof. The casing 64 also has flanged outer edges 68 which are adapted to be secured to the lower surface of the cover 49 in such manner as to secure the upper extremity of the divider element 66 against a longitudinally extending intermediate part of the cover 49. The divider element 66 is formed to provide parallel side walls dividing the space between the casing 62 and the cover 49 into parallel chambers indicated at 69, 71 and 72. Opposite ends of the side Walls of the divider 66 terminate in spaced relation to the ends of the casing 64 to provide openings by which the parallel chambers 69, 71 and 72 form one continuous chamber extending rearwardly, forwardly and rearwardly with respect to a longitudinal axis of the engine. The foreward end of the chamber 69 is provided with an inlet formed by a plurality of louvres 73 which are formed at one side of and adjacent the forward end of the casing 64. The middle chamber 71 is filled with filtering material indicated at 74. The rear end of the chamber 72 has an outlet formed by upwardly mpressing the cover plate 49 as is indicated at 76. The impression 76 has an opening in the rear wall thereof in WhlCh a coupling element 77 is secured. The coupling element is adapted to have secured therein the draft tube indicated at 63. The draft tube 63 is formed in such a way as to extend downwardly and at one side of the rear end of the engine and the lower end thereof provides an obliquely disposed outlet indicated at 78.

It will be apparent that air tending to move upwardly within the rear compartment 53 will flow into the continuous passage formed by the chambers 69, 71 and 73 through the louvres indicated at 73. The casing 64 is also formed in such manner as to provide a single louvre 79 at the rear end of the middle compartment 71. As the air which enters the louvres 73 flows rearwardly through the passage 69 and turns the bend, it must turn to enter and to flow forwardly within the passage 71 and there will be separated from the air any heavy particles of oil that may be entrained therein. These oil particles will collect on the end wall of the casing 79 and will return to the crankcase of the engine through the louvre 79. In the passage 71 the filter 74 will also collect any oil particles that are not separated by centrifugal force and collected on the end wall of the casing 64. The smaller particles collected in the filter 74 will flow downwardly by gravity in the filter material and will flow along the upper surface of the casing 74 to the rear of the engine and return to the crankcase through the louvre 79. From the front end of the passage 71 the air will flow outwardly and into the forward end of the passage 72 where thereafter it will be exhausted from the engine through the outlet formed by the depression 76 and the draft tube 63. In addition to the circulation of air downwardly and upwardly through the compartments 52 and 53 respectively, and caused by the fan 59, it will be apparent that there will also be an induced'draft upon the compartments 52 and 53 and caused by the obliquely disposed end 78 of the draft tube 63. When the engine 10 moves forwardly as would occur when the engine might be used as in propelling a motor vehicle or other similar device the forward movement of the obliquely disposed end 78 of the draft tube 73 will tend to entrain air from within the opening 78, thereby causing a reduced pressure in the end of the tube 63 which will result in an induced as well as a forced circulation throughout the crankcase and camshaft gallery of the engine.

In order to prevent oil from the crankcase of the engine from splashing into the filler tube 56 it is proposed to employ a bafile 79 which may be secured at the edges thereof to the lower surface of the cover 49 and which may open rearwardly or otherwise along the lower surface of the cover 49. The baffle 79 is adapted to extend across the lower end of the tube 56 so that any oil which may splash upwardly from the crankcase of the engine will not flow outwardly through the filler tube 56.

It will be apparent that air which circulates downwardly through the front compartment 52 and upwardly through the rear compartment 53 and across the front and rear ends of the camshaft gallery and crankcase of the engine will pick up any vaporized fuel which may escape around the engine pistons 26 and any vaporized or atomized lubricating oil that may be thrown outwardly from the bearings of the engine and will carry these vapors and atomized particles into the separating element forming a part of the outlet passage indicated at 51. In the separating element 62 the vapors will be condensed and collected upon the various surfaces of the filter element and will be returned to the crankcase through the louvre 79. The air and the lighter particles of the fuel may not be condensed and will flow from the engine through the draft tube 63.

I claim:

1. A crankcase ventilation system for engines comprising a camshaft gallery and a crankcase formed in an engine block having obliquely disposed rows of cylinders, said block being formed between the adjacent sides of said rows of cylinders to provide an elongated passage extending from the front wall to the rear wall of said block, a transversely disposed wall extending across said block and intermediate said end walls and dividing said camshaft gallery and said crankcase into vertically extending front and rear compartments, said camshaft gallery and said crankcase in each of said compartments being adapted to communicate with one another through one end of said elongated passage, said wall being formed to terminate above the lower extremity of said crankcase to provide beneath said wall a communicating passage between said front and rear compartments, an inlet passage formed in the upper Wall enclosing said camshaft gallery and communicating with the upper part of said front compartment, and anoutlet passage formedin saidupper Wall enclosing said' camshaft gallery and communicating with the upper part of said rear compartment.

2. A crankcase ventilation system for engines comprising a camshaft gallery and a crankcaseformed in an engine block having obliquely disposed rows of cylinders, said block being formed between the adjacent-sides of said rows of cylinders to provide an elongated passage extending from the front wall to the rear wall of said block, a transversely disposed wall extending, across said block between said end walls and dividing said camshaft gallery and said crankcase into vertically disposed front and rear compartmentscommunicating with one another through said elongated passage, said dividing wall being formed to terminate above the lower extremity of said crankcase to provide beneath said dividing wall a communicating passage between said front and rear compartments, an inlet passage formed in the upper wall enclosing said camshaft gallery and communicating with the upper part of said front compartment, and an outlet passa e formed in said upper part enclosing said camshaft gallery and communicating with the upper part of said rear compartment.

3. A crankcase ventilation system for engines comprising a camshaft gallery and a crankcase formed in an engine block having obliquely disposed rows of cylinders, said block being formed between the adjacent sides of said rows of cylinders to provide an elongated passage extending from the front wall to the rear wall of said block, a transversely disposed wall extending across said block and substantially midway between said end walls and dividing said camshaft gallery and said crankcase into vertically extending front and rear compartments, said camshaft gallery and said crankcase being adapted to communicate with one another in each of said compartments through one end of said elongated passage, said wall being formed to terminate above the lower extremity of said crankcase to provide beneath said wall a communicating passage between said front and rear compartments, an inlet passage formed in the upper Wall enclosing said camshaft gallery and communicating with the upper part of said front compartment, and an outlet passage formed in said upper wall enclosing said camshaft gallery and communicating with the upper part of said rear compartment, conduit means communicating with said outlet passage, said conduit means being formed to provide an outlet opening to the atmosphere in a direction opposite the movement of the air flow resulting from the move. ment of said engine.

4. A crankcase ventilating system for engines comprising a camshaft gallery and a crankcase formed in an engine block having obliquely disposed rows of cylinders, said block being formed between the adjacent sides of said rows of cylinders to provide an elongated passage extending from the front wall to the rear wall of said block, a transversely disposed wall extending across said block and intermediate said end walls and dividing said camshaft gallery and said crankcase into vertically extending front and rear compartments, said camshaft gallery and said crankcase being adapted to communicate with one another in each of said compartments through one end of said elongated passage, a communicating passage extending between said front and rear compartments and formed in said engine adjacent the lower extremity of said dividing wall, means for supplying air to the upper part of said front compartment, and means for exhausting air from the upper part of said rear compartment.

5. A crankcase ventilation system for engines comprising a camsnaft gallery and a crankcase formed in an engine block having spaced and parallel rows of cylinders formed therein, said block being formed between said rows of cylinders to provide passage means at each end of said block and extending between said camshaft gallery and said crankcase, a transversely disposed wall extending across said block between said passage means and dividing said camshaft gallery'and Said crankcase into vertically extending. front and rear compartments, a passage formed across said wall and in the lower part of said crankcase and between the lower ends of said compartments, outlet passage means formed inthe opposite end of one of said compartments and in an upper wall enclosing said camshaft gallery, oil separator means insaid outlet passage means, said outlet passage means being formed to provide a drain from said oil separator means to the interior of said camshaft gallery, and inlet passage means communicating with the opposite end of the other of said compartments for supplying air to said' compartments.

6. A crankcase ventilation system for engines comprising a camshaft gallery and a crankcase formed in an engine block having spaced and parallel rows of cylinders formed therein, a cover plate for said camshaft gallery, inlet passage means formed in one end of said cover plate for admitting air to said camshaft gallery, outlet passage means formed in the opposite end of said cover plate for discharging crankcase vapors from said camshaft gallery to the atmosphere, oil separator means in said outlet passage means for separating oil from said crankcase vapors, drain means formed in said outlet passage means for draining said oil into said camshaft gallery, and means for circulating air throughout said camshaft gallery and said crankcase and between said inlet passage means and said outlet passage means.

7. A crankcase ventilation system for engines comprising a camshaft gallery and a crankcase formed in an engine block having spaced and parallel rows of cylinders formed therein, a cover for the upper part of said camshaft gallery and being adapted to be removably secured to said block between said rows of cylinders, a casing secured to the lower part of said cover plate at one end of said camshaft gallery and having partition means therein dividing the interior of said easing into a continuous chamber having a middle section and two side sections, filter means in said middle section of said continuous chamber, means for admitting crankcase vapors to one of said side sections at one end of said continuous chamber, means for discharging crankcase vapors through said cover plate and from the other of said side sections and adjacent the opposite end of said continuous chamber, and means for circulating air throughout said crankcase and said camshaft gallery and to the atmosphere through said continuous chamber.

8. A crankcase ventilation system for engines comprising a camshaft gallery and a crankcase formed in an engine block having spaced and parallel rows of cylinders, said block being formed between said rows of cylinders to provide a first communicating passage means between said camshaft gallery and said crankcase at each end of said camshaft gallery and said crankcase, a transversely disposed wall extending across said block and dividing said camshaft gallery and said crankcase into vertically extending front and rear compartments, a second communicating passage means eXtending between adjacent ends of said compartments, an outlet passage formed in one of said compartments and disposed on the opposite side of the horizontal centerline of said engine from the second communicating pas sage means, and means responsive to the operation of the engine to supply atmospheric air to the other of said compartments at an end similarly disposed on the opposite side of the horizontal center-line of said engine from the second communicating passage means.

9. A crankcase ventilation system for engines according to claim 8 and including an oil separator means in said outlet passage.

10. A crankcase ventilation system for engines comprising a camshaft gallery and a crankcase formed in 7 an engine block having spaced and parallel rows of cylinders, said block being formed between said rows of cylinders to provide communicating passage means between said camshaft gallery and said crankcase at each end of said engine block, a transversely disposed wall extending across said block and dividing said camshaft gallery and said crankcase into vertically extending front and rear compartments, communicating passage means extending between adjacent ends of said compartments, an outlet passage formed in one of said compartments and disposed on the opposite side of the horizontal center-line of said engine from the communicating passage means extending between adjacent ends of said com- 8 partments, inlet means for supplying atmospheric air to the other of said compartments at an end disposed on the opposite side of the horizontal center-line of said engine from the communicating passage means extending between adjacent ends of said compartments, and a fan for cooling said engine, said fan being positioned with respect to said engine to direct air into said inlet means.

References Cited in the file of this patent UNITED STATES PATENTS 1,872,609 Schittke Aug. 16, 1932 

